Evaporust is THE best way to deal with rusted legs. But for a single pin - one and done - its not cost effective. Its like $20+ for a gallon (which won't fill the PVC tube recommended) and another $20 for the materials to make it -- plus your time. I have the PVC solution and two gallons of Evaporust in it and its great but I've done many pins and will do more. Start with the basic approach -- steel wool and some sudsy water will get it off. If its much worse then work your way up with the chemicals. Or buy shiny new for $12 each.
After rust us off -- good rinse, let dry, then coat of wax with stop rust from coming back -- cuz it will.
BTW - rubbers last many years. I have some pins I installed new rubber kit over 10 years ago and they are good.